Dear Jerico,
The import means to restore. During restore, you will be asked to define a template where you can
locate the source backup medium.
Here I have a document about how to restore via database manager. You can have a look and the basic is the same with the database studio
Please change the txt to pdf version to read.
Two points need to remember (they are also mentioned in the note you mentioned), 1 use initialize database option to restore, 2 before restarting database you need to load sys data as mentioned
Best regards,
James